Selective position top-down cementing tool

ABSTRACT

A cementing system and method for selectively providing bottom-up cementing and top-down cementing of a liner during a single downhole trip are provided. The cementing system has three configurations. A first configuration of the tool allows fluid flow through a central flowbore of the cementing tool, a liner hanger setting tool below the cementing tool, and the liner. A second configuration of the tool routes fluid from the central flowbore of the cementing tool to an annulus surrounding the liner hanger setting tool and the liner. A third configuration of the tool reestablishes flow through the central flowbore of the cementing tool and enables a dropped ball to reach the liner hanger setting tool.

CROSS-REFERENCE TO RELATED APPLICATION

The present application claims priority to and the benefit of U.S.Provisional Application Ser. No. 62/901,873, entitled “SelectivePosition Top-Down Cementing Tool,” filed on Sep. 18, 2019.

TECHNICAL FIELD

The present disclosure relates generally to a cementing tool for usewith a liner hanger and, more particularly, to a selective positiontop-down cementing tool for use with a liner hanger.

BACKGROUND

When drilling a well, a borehole is typically drilled from the earth'ssurface to a selected depth and a string of casing is suspended and thencemented in place within the borehole. A drill bit is then passedthrough the initial cased borehole and is used to drill a smallerdiameter borehole to an even greater depth. A smaller diameter casing isthen suspended and cemented in place within the new borehole. This isconventionally repeated until a plurality of concentric casings aresuspended and cemented within the well to a depth which causes the wellto extend through one or more hydrocarbon producing formations.

Rather than suspending a concentric casing from the bottom of theborehole to the surface, a liner is often suspended adjacent to thelower end of the previously suspended casing, or from a previouslysuspended and cemented liner, so as to extend the liner from thepreviously set casing or liner to the bottom of the new borehole. Aliner is defined as casing that is not run to the surface. A linerhanger is used to suspend the liner within the lower end of thepreviously set casing or liner.

A running and setting tool disposed on the lower end of a work stringmay be releasably connected to the liner hanger, which is attached tothe top of the liner. The work string lowers the liner hanger and linerinto the open borehole until the liner reaches a desired location. Oncethe liner reaches the desired location, the liner may be cemented in theborehole and against the previous casing. Cement is typically pumpeddown the bore of the work string and liner and up the annulus formed bythe liner and open borehole. As deeper wells are drilled and longerliners are utilized, cement is circulated through the liner assembly athigher pressures to reach the bottom of the liner and flow back up theannulus. When a liner is set within a borehole, the cement being pumpedto secure the liner in place can potentially exceed the pore pressure ofthe formation through which the borehole extends. Low pore pressure orthief zones severely limit the pressure that may be applied whilecementing such that it may not be possible to circulate cement up theentire backside height of the liner. This can inhibit the ability toproperly and completely conduct a well cementing operation usingtraditional bottom-up cement circulation.

It is now recognized that a need exists for a liner cementing tool thatcan be selectively configured for traditional liner cementing ortop-down liner cementing.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of the present disclosure and itsfeatures and advantages, reference is now made to the followingdescription, taken in conjunction with the accompanying drawings, inwhich:

FIG. 1 is a schematic illustration of a liner installation work stringincluding a liner hanger assembly coupled to a cementing tool being usedto cement a liner in a well with low pore pressure, in accordance withan embodiment of the present disclosure;

FIG. 2 is a schematic illustration of the work string of FIG. 1 with thecementing tool being used to facilitate top-down cementing, inaccordance with an embodiment of the present disclosure;

FIG. 3 is a schematic illustration of the work string of FIG. 1 with aball that has passed through the cementing tool being used to set aliner hanger, in accordance with an embodiment of the presentdisclosure;

FIGS. 4A-4B are cross-sectional views of a cementing tool for use in thework string of FIGS. 1-3, the cementing tool being in a run-in position,in accordance with an embodiment of the present disclosure;

FIGS. 5A-5B are cross-sectional views of the cementing tool of FIGS.4A-4B with a first ball landed and providing top-down cementing throughan annulus, in accordance with an embodiment of the present disclosure;

FIGS. 6A-6B are cross-sectional views of the cementing tool of FIGS.4A-5B with a second ball landed, in accordance with an embodiment of thepresent disclosure;

FIGS. 7A-7B are cross-sectional views of the cementing tool of FIGS.4A-6B with internal components of the cementing tool shifting downward,in accordance with an embodiment of the present disclosure;

FIGS. 8A-8B are cross-sectional views of the cementing tool of FIGS.4A-7B with internal components of the cementing tool shutting a flowpath to the annulus surrounding the cementing tool, in accordance withan embodiment of the present disclosure;

FIGS. 9A-9B are cross-sectional views of the cementing tool of FIGS.4A-8B releasing the first ball, in accordance with an embodiment of thepresent disclosure;

FIGS. 10A-10B are cross-sectional views of the cementing tool of FIGS.4A-9B shifting to a position that re-establishes flow through a centralflowbore, in accordance with an embodiment of the present disclosure;

FIG. 11 is a cross-sectional view of the cementing tool of FIG. 4A takenat line A-A, in accordance with an embodiment of the present disclosure;and

FIG. 12 is a cross-sectional view of the cementing tool of FIG. 4B takenat line B-B, in accordance with an embodiment of the present disclosure.

DETAILED DESCRIPTION

Illustrative embodiments of the present disclosure are described indetail herein. In the interest of clarity, not all features of an actualimplementation are described in this specification. It will of course beappreciated that in the development of any such actual embodiment,numerous implementation specific decisions must be made to achievedevelopers' specific goals, such as compliance with system related andbusiness related constraints, which will vary from one implementation toanother. Moreover, it will be appreciated that such a development effortmight be complex and time consuming, but would nevertheless be a routineundertaking for those of ordinary skill in the art having the benefit ofthe present disclosure. Furthermore, in no way should the followingexamples be read to limit, or define, the scope of the disclosure.

Certain embodiments of the present disclosure may be directed to acementing system and method for selectively providing bottom-upcementing and top-down cementing of a liner during a single downholetrip. The disclosed cementing system is an accessory tool designed to beused in conjunction with liner installations, and it is specificallydesigned to facilitate one-trip top-down cementing for wells formedthrough formations with low pore pressure (or expected low porepressure).

The disclosed cementing tool includes a body with a first seat, a secondseat, and a shifting sleeve assembly disposed internal to the body, andone or more ports extending through the body. The first seat isconfigured to receive a ball landed thereon, and the second seat isconfigured to receive a ball, dart, or plug landed thereon. The shiftingsleeve assembly is configured to selectively transition the cementingtool from a first operating mode to a second operating and from thesecond operating to a third operating mode.

As such, the disclosed cementing system has three possibleconfigurations. A first configuration (i.e., the first operating mode)of the tool allows fluid flow through a central flowbore of thecementing tool, a liner hanger setting tool below the cementing tool,and the liner. In the first operating mode, the central flowbore of thecementing tool is open, enabling fluid flow through the centralflowbore. This first configuration may be used to provide traditionalbottom-up cementing. A second configuration (i.e., the second operatingmode) of the tool routes fluid from the central flowbore of thecementing tool to an annulus surrounding the liner hanger setting tooland the liner. Specifically, in the second operating mode, at least aportion of the central flowbore is closed and the one or more ports areopen directing fluid flow outside of the cementing tool. This secondconfiguration may be used to provide top-down cementing when, forexample, relatively low pore pressures are expected in the wellbore towhich the liner is being cemented. A third configuration (i.e., thethird operating mode) of the tool provides flow through the centralflowbore of the cementing tool and enables a dropped ball to reach theliner hanger setting tool. In the third operating mode, the shiftingsleeve forms an internal flow path that circumvents the second seat,thereby enabling fluid flow through the central flowbore of thecementing tool. This third configuration may be used to set the linerhanger and/or to re-establish flow through the central flowbore of thecementing tool.

Although all three of these configurations are possible using thedisclosed cementing tool, there is no requirement that the tool beplaced in the second configuration and then the third configuration forsetting the liner hanger. The disclosed cementing tool may be used forboth fully traditional cementing operations as well as for bottom-up andtop-down cementing operations, depending on the pore pressure of thewellbore. In instances where the pore pressure of the well is such thata top-down cement job is not necessary, then the disclosed cementingtool may be operated without ever being switched to the secondconfiguration and third configuration. The cementing tool may beoperated to perform a traditional fully bottom-up cement job, afterwhich a relatively small sized ball or dart is landed in the linerhanger setting tool to set the liner while the cementing tool is stillin its initial configuration. As such, the tool can be either switchedfrom the first configuration to the second configuration and then to thethird configuration, or the entire cementing operation may be performedwith the tool in the first configuration, depending on the operationalneeds of the tool. The disclosed cementing tool therefore providesflexibility for use in different wellbores, as compared to existingtop-down cementing tools.

In instances where the disclosed cementing tool is used to providetop-down cementing, the cementing tool may be switched from the firstconfiguration to the second configuration via a dropped ball, whichallows the cementing tool to begin top-down cementing immediately afterfinishing an initial bottom-up cementing phase and without waiting forthe bottom cement to dry. During a top-down cementing operation in whichthe cementing tool is in the second configuration, cement is routeddirectly from drill pipe into the annulus and does not flow through theliner hanger setting tool. The disclosed cementing tool may be switchedfrom the second configuration to the third configuration using either adropped ball or a dart, which may be used to clear cement from the innerdiameter of the drill pipe. Compared to existing top-down cementingtools, the disclosed cementing tool provides faster operating times andless potential for obstructing the central flowbore.

Turning now to the drawings, FIG. 1 illustrates an example linerinstallation work string 100 that may utilize the disclosed cementingtool 102. The work string 100 is positioned within a casing 104 in awellbore 106, as shown. The work string 100 includes the cementing tool102 and a liner hanger setting tool 108. During run-in, the liner hangersetting tool 108 is attached to a liner hanger 110 from which a liner112 extends downward. The cementing tool 102 and liner hanger settingtool 108 may be supported in the wellbore 106 on a string of drill pipe114 having a bore and a central axis 116. As illustrated, the disclosedcementing tool 102 is disposed above the liner hanger setting tool 108(e.g., attached between the drill pipe 114 and the liner hanger settingtool 108).

FIGS. 1-3 are schematic illustrations with the left-hand side half ofthe work string 100 illustrated as a front view and the right-hand sidehalf of the work string 100 illustrated in a schematic section view. Assuch, the left-hand side half of the work string 100 shows the outsideof the cementing tool 102, liner hanger 110, and liner 112, while theright-hand side half shows the inside of the cementing tool 102, linerhanger setting tool 108, and liner 110. Although FIGS. 1-3 provide asimplified line drawing of the basic internal components of the workstring 100, FIGS. 4A-13 illustrate a more detailed version of thecementing tool 102 of FIGS. 1-3.

The cementing tool 102 may include a series of shifting sleeve(s),ball/plug seats, and ports that facilitate shifting the cementing tool102 selectively between enabling flow through a central flowbore 118 ofthe cementing tool 102 and enabling flow into an annulus surrounding thecementing tool 102. In this way, the cementing tool 102 supports bothtraditional bottom-up liner cementing operations as well as top-downliner cementing operations. The disclosed cementing tool 102 may beparticularly useful when cementing and setting a liner 112 in a wellbore106 passing through formations 120 that have or are expected to have alow pore pressure.

If a well is expected to extend through a formation 120 with a low porepressure, the disclosed cementing tool 102 is run in the installationwork string 100 above the liner hanger setting tool 108 as shown. FIG. 1shows the work string 100 during run-in. While the work string 100 isbeing run to the liner setting location, the cementing tool 102 is in afirst configuration such that a flowpath is open through the centralflowbore 118 of the cementing tool 102 connecting the drill pipe 114 tothe liner hanger setting tool 108. Once the work string 100 is at thedesired downhole location for cementing and setting the liner 112,cement may be circulated (arrows 122) down through the drill pipe 114,central flowbore 118 of the cementing tool 102, liner hanger settingtool 108, and out the bottom of the liner 112. This provides a bottom-upcementing operation where the cement is circulated into an annulus 124outside the liner 112. Due to the pore pressure of the formation 120, itmay not be possible to complete the entire cementing job via thistraditional bottom-up cementing operation. Line 126 illustrates amaximum height to which cement may be pumped before exceeding a porepressure of the formation 120 and causing leak-off.

If cement pumping pressures start to approach the pore pressure of theformation 120 and the liner 112 can only be cemented up to the thiefzone (e.g., the maximum height 126), the cementing tool 102 may beswitched to a second configuration to complete the cement job via atop-down cementing operation. FIG. 2 illustrates the cementing tool 102in the second configuration. To switch the cementing tool 102 from thefirst configuration of FIG. 1 to the second configuration of FIG. 2, aball 200 is dropped/pumped down the work string 100. The ball 200 landsin a lower seat 202 of the cementing tool 102, thereby closing off flowthrough the central flowbore (118 in FIG. 1) of the cementing tool 102.After the ball 200 is landed in the seat 202, pressure is applied downthe work string 100 to actuate a shifting sleeve assembly that shiftsthe cementing tool 102 from the first configuration to the secondconfiguration, opening ports 204 in an external body 206 of thecementing tool 102 so that fluid flow may be routed from the centralflowbore of the cementing tool 102 directly into the annulus 124 betweenthe work string 100 and the existing casing 104 and open hole below.

Once the cementing tool 102 is in the second configuration of FIG. 2,cement may be circulated (arrows 208) down through the drill pipe 114and then from the cementing tool 102 directly into the annulus 124,without passing through the liner hanger setting tool 108 or liner 112.This provides a top-down cementing operation where the cement isreleased into the annulus 124 from a point above the liner 112. Theannulus 124 is closed off at the wellhead at this time, and any cementnow pumped down the work string 100 is directed into the annulus 124between the top of the liner 112 and the thief zone (at line 126). Thecement is pumped down the annulus 124 until it reaches a lower cementedportion 210 that was previously cemented from below. As the liner 112 iscemented from both below and above the thief zone (126), the cement jobis completed.

After the cement job is complete, the cementing tool 102 may be switchedto a third configuration to reestablish flow through the work string 100and set the liner hanger 110. FIG. 3 illustrates the cementing tool 102in the third configuration. To switch the cementing tool 102 from thesecond configuration of FIG. 2 to the third configuration of FIG. 3, asecond ball 300 is dropped/pumped down the work string 100. The ball 300lands in an upper seat 302 of the cementing tool 102, thereby closingoff flow through the central flowbore (118 in FIG. 1) of the cementingtool 102 above the lower ball seat 202. After the ball 300 is landed inthe seat 302, pressure is applied down the work string 100, causing theshifting sleeve assembly to shift the cementing tool 102 from the secondconfiguration to the third configuration, closing off the ports 204 inthe external body 206 of the cementing tool 102 and shifting varioussleeves and component of the cementing tool 102 to release the firstball 200 from the lower ball seat 202. This closes off flow into theannulus 124 while reestablishing flow through the cementing tool 102.This shifting of the cementing tool 102 also releases the ball 200 thathad previously been landed in the lower seat 202 to travel down the workstring 100 and land in a seat 304 of the liner hanger setting tool 108.Pressure is then applied (arrows 306) through the work string 100 toactuate the liner hanger setting tool 108 that sets the liner hanger110.

As discussed above, the disclosed cementer 102 has three mainconfigurations (or operating modes), with the first position allowingtraditional bottom-up circulation of cement, the second position routingcement into the annulus 124 in a top-down manner, and the third positionrestoring flow through the bottom of the cementing tool 102 and towardthe liner hanger setting tool 108 to set the liner hanger 110.

In some instances, the disclosed cementing tool 102 may be included in awork string 100 that is lowered through a well with formation porepressures that are high enough that top-down cementing (as shown in FIG.2) is not required to complete the cement job. If it is determined thatno top-down cement job is necessary, the cementing tool 102 may be keptin the first configuration (as shown in FIG. 1) throughout the entirecement job and while the liner hanger setting tool 108 is actuated. Itis not necessary to shift the cementing tool 102 from the first tosecond configuration and from the second to third configuration toenable actuation of the liner hanger setting tool 108. Instead, thecementing tool 102 may be kept in the first configuration, and arelatively smaller sized ball or dart (smaller than ball 200) may be runthrough the work string 100 to land directly in the seat 304 of theliner hanger setting tool 108. The disclosed cementing tool 102 is thusnever activated into the top-down cementing mode (second configuration).This decreases a risk of tool leakage that might otherwise occur usingtop-down cementing tools that must be shifted through each operatingconfiguration before setting the liner hanger.

Having generally described the operation of the disclosed cementing tool102 within the context of a liner installation work string 100, a moredetailed description of the structure and function of shifting thecementing tool 102 between the first, second, and third configurationswill now be provided. Reference will be made to FIGS. 4A-10B, whichillustrate an embodiment of the cementing tool 102 as it is transitionedfrom a run-in position (first configuration) shown in FIGS. 4A-4B to atop-down cementing position (second configuration) shown in FIGS. 5A-5Band finally to a flow reestablishing position (third configuration)shown in FIGS. 10A-10B. Although a series of sleeves, shear screws, andother load lugs, and other components form the disclosed “shiftingsleeve assembly” in FIGS. 4A-10B, it should be understood that othercombinations of components may be utilized in other embodiments toprovide the disclosed shifting of the cementing tool 102 between itsthree operating modes.

FIGS. 4A-4B illustrate the cementing tool 102 in the first configurationdescribed above. This is the configuration in which the cementing tool102 is run downhole, performs traditional bottom-up cement circulation,and if no top-down cementing is needed, allows a ball or dart to passtherethrough for actuating the below liner hanger setting tool.

The cementing tool 102 may include, among other things, an upper bushing400, the external body 206, a lower bushing 402, a shear sleeve 404, alocating sleeve 406, a dog seal mandrel 408, a lock sleeve 410, arelease sleeve 412, a lower dog seal mandrel 414, a piston connector416, a ball sleeve 418, a rotating ball assembly 420, a ball mandrel421, a shift sleeve 422, and a bottom guide 423. The external body 206includes ports 204 at an axial location thereof, and houses the internalcomponents of the cementing tool 102. The upper and lower bushings 400and 402 may be threaded or otherwise connected to opposite ends of thebody 206. The upper and lower bushings 400 and 402 may function asconnectors for connecting the cementing tool 102 between the drill pipeand liner hanger setting tool (as shown in FIGS. 1-3).

The dog seal mandrel 408, the lower dog seal mandrel 414, and the pistonconnector 416 are located inside a bore of the body 206 and may beconnected to each other end to end, e.g., via threads. Specifically, thelower dog seal mandrel 414 is generally connected between the dog sealmandrel 408 at its upper end and the piston connector 416 at its lowerend. The dog seal mandrel 408 may include one or more flow pathsextending therethrough (e.g., from a radially inner edge to a radiallyouter edge thereof). For example, the dog seal mandrel 408 may include aplurality of circulation slots 424 formed therethrough at a certainaxial position. As illustrated, the circulation slots 424 extendingthrough the dog seal mandrel 408 may be inclined with respect to aradial direction perpendicular to the longitudinal axis of the cementingtool 102. This inclined orientation may help to direct flow around aball seat (e.g., 302 of FIG. 3) when the cementing tool 102 in its thirdconfiguration. One or more load lugs 426 may extend in a radiallyoutward direction from the dog seal mandrel 408. The one or more loadlugs 426 may be positioned at an axial position located above the axialposition of the slots 424. A locking mechanism 428 may be disposedaround an outer diameter of the dog seal mandrel 408. The lockingmechanism 428 may be positioned at an axial position located below theaxial position of the slots 424. In the illustrated embodiment, thelocking mechanism 428 may be a c-ring assembly. However, other types oflocking mechanisms 428 may be used in other embodiments. The lower dogseal mandrel 414 may include one or more ports 429 formed therethroughat an axial location.

As illustrated, the shear sleeve 404, the locating sleeve 406, and thelock sleeve 410 may each be disposed within an annular space between anouter diameter of the dog sleeve mandrel 408 and an inner diameter ofthe body 206. The shear sleeve 404 may extend at least partiallyinternal to the locating sleeve 406 in a radial direction. The locatingsleeve 406 may be attached in an axial direction to the lock sleeve 410at its lower end, as shown. An alternating series of bonded seals 430and spacers 432 may be located radially between an outer diameter of thelower dog seal mandrel 414 and an inner diameter of the body 206. One ofthe spacers 432A may include one or more ports 434 formed therethrough.For example, in the illustrated embodiment, the spacer 432A includes aplurality of ports 434 positioned circumferentially around the spacer432A and extending radially through the spacer 432A. In the run-inconfiguration of FIGS. 4A-4B, the port(s) 434 are not aligned (e.g., notlocated at a same axial location) with the ports 204 through the body206.

The release sleeve 412 may be located within a bore of one or both ofthe upper bushing 400 and the dog seal mandrel 408. The release sleeve412 may include one or more flow paths extending therethrough (e.g.,from a radially inner edge to a radially outer edge thereof). Forexample, the release sleeve 412 may include a plurality of slots 436formed therethrough at a certain axial position. As illustrated, theslots 436 extending through the release sleeve 412 may be inclined withrespect to a radial direction perpendicular to the longitudinal axis ofthe cementing tool 102. This inclined orientation may help to directflow around a ball seat (e.g., 302 of FIG. 3) when the cementing tool102 in its third configuration. The slots 436 may be oriented at anincline equivalent to the incline of the slots 424 through the dog sealmandrel 408. The slots 436 may be positioned at the same circumferentialpositions around the release sleeve 412 as the slots 424 are around thedog seal mandrel 408. The release sleeve 412 may include a D-seal 438 atan upper end thereof that is configured to seal against the innerdiameter of the upper bushing 400 at certain points during shifting ofthe cementing tool 102. One or more keys 440 may extend radially inwardfrom the dog seal mandrel 408 into one or more corresponding grooves inan outer diameter of the release sleeve 412.

The piston connector 416 may axially attach a lower end of the lower dogseal mandrel 414 to an upper end of the ball sleeve 418. The pistonconnector 416 may be connected to each of these components 414 and 418via threads, as shown. However, other types of connectors may be used toattach the lower dog seal mandrel 414 to the ball sleeve 418 in otherembodiments. The piston connector 416 and the ball sleeve 418 may eachabut the rotating ball assembly 420. The rotating ball assembly 420 mayinclude, among other things, an upper seat 442, a lower seat 444, arotatable ball 446, and a compression spring 448. The rotatable ball 446is initially seated between the upper and lower seats 442 and 444 in anorientation where a restricted flow path is provided through the ball446. As such, the ball 446 may function as the lower seat 202 of thecementing tool 102 described above with reference to FIG. 2. Thecompression spring 448 may be located axially between a lower end of thepiston connector 416 and shoulder of the upper seat 442. The overallball assembly 420 may be of a similar type and function to the downholeball circulation tool disclosed within U.S. Pat. No. 7,318,479 to TIWCorporation, which is hereby incorporated by reference. The rotatingball assembly 420, upon actuation, may rotate the ball 446 such that theball 446 is then seated between the upper and lower seats 442 and 444 inan orientation where an enlarged flow path is provided through the ball446.

The ball mandrel 421 may be located radially between an outer diameterof the lower seat 444 and an inner diameter of the shift sleeve 422. Theshift sleeve 422 may be located radially between the outer diameter ofthe ball mandrel 421 and the inner diameter of the body 206. The bottomguide 423 may be connected to a lower end of the ball mandrel 421, and alower end of the bottom guide 423 may extend into the bore of the lowerbushing 402. As illustrated, the shift sleeve 422 may include one ormore grooves 449 formed into an inner diameter thereof at a certainaxial position. The ball mandrel 421 may include one or more releasedogs 450 biased in a radially outward direction from the ball mandrel421, and in the run-in configuration these release dogs 450 may be heldagainst an inner diameter of the shift sleeve 422 (i.e., axially offsetfrom the one or more grooves 449).

Having described the general structure of the cementing tool 102 ofFIGS. 4A-10B, a detailed description of the operations of the cementingtool 102 moving between various configurations will now be provided. Asmentioned above, FIGS. 4A-4B show the cementing tool 102 in the firstconfiguration in which the system is run into the well and used toprovide any bottom-up cementing operations. To that end, the cementingtool 102 allows flow straight through the inner flowbore of thecementing tool 102 (e.g., through each of the upper bushing 400, releasesleeve 412, lower dog seal mandrel 414, rotating ball assembly 420,bottom guide 423, and lower bushing 402).

FIGS. 5A-5B illustrate the cementing tool 102 once it has shifted to thesecond configuration for top-down cementing. The process of shifting thecementing tool 102 from the first configuration (run-in) to the secondconfiguration (top-down cementing) may involve the following steps.First, the ball 200 is dropped and pumped into the central flowbore ofthe cementing tool 102 until it catches on the seat 202 formed by therotating ball 446. In some embodiments, an outer diameter of the ball200 may be between approximately 1.5 and 5 inches, more particularlybetween approximately 2.5 and 4 inches, or more particularlyapproximately 3.25 inches. Regardless of the exact size of the ball 200,the ball 200 is large enough to seat on and block flow through therestricted flowpath of the rotating ball 446 but small enough to passthrough the enlarged flowpath of the rotating ball 446 and the upperseat 302 formed along the internal diameter of the release sleeve 412.

Landing the ball 200 in the seat 202 allows pressure to build behind apiston assembly 490 of the cementing tool 102. This piston assembly 490may include one or more internal components of the cementing tool 102.For example, in the illustrated embodiment, the piston assembly 490 mayinclude the rotating ball assembly 420, the ball mandrel 421, the dogseal mandrel 408, the release sleeve 412, the lower dog seal mandrel414, the piston connector 416, the ball sleeve 418, the shift sleeve422, the bottom guide, and/or other attached components. An outerdiameter of the hydraulic piston area for this piston assembly 490 isdefined by an interface between an o-ring 500 at an outer diameter ofthe ball mandrel 421 and the inner diameter of the body 206.

Once pressure is applied behind the ball 200, a downward force istransferred through the piston assembly 490. This downward force shearsone or more shear screws located between an inner diameter of the shearsleeve 404 and an outer diameter of the dog seal mandrel 408. Althoughthe one or more shear screws are not visible in the view of FIGS. 5A-5B,such shear screws 550 are shown in FIG. 11. FIG. 11 is a section view ofthe cementing tool 102 taken at line A-A of FIG. 4A before the shearscrew(s) 550 have been sheared (i.e., when the cementing tool 102 isstill in the first configuration). Upon shearing the shear screw(s) 550between the shear sleeve 404 and the dog seal mandrel 408, the pistonassembly 490 is able to move axially downward relative to the body 206of the cementing tool 102 by a certain amount, as shown in FIGS. 5A-5B.For example, in some embodiments, the dog seal mandrel 408 and otherattached components of the piston assembly 490 may shift axiallydownward by an amount between approximately 2 inches and 5 inches, moreparticularly between approximately 3 inches and 4 inches, or moreparticularly approximately 3.640 inches. This downward motion may bestopped when the load lugs 426 in the dog seal mandrel 408 contact ashoulder 502 on an inner diameter of the locating sleeve 406.

In addition, the downward motion of the piston assembly 490 may causethe locking mechanism 428 (e.g., c-ring assembly) on the outside of thedog seal mandrel 408 to move along an inner diameter of the lock sleeve410. The c-ring assembly 428 may include a retainer with a c-ringdisposed therein, wherein the c-ring is biased in a radially outwarddirection but is able to be compressed in a radially inward direction tobe received further into the retainer. As the c-ring assembly 428 movesaxially downward with the rest of the piston assembly 490, it passes aprofile 504 formed on the inner diameter of the lock sleeve 410. Thisprofile 504 may force the c-ring of the c-ring assembly 428 into acompressed position until the c-ring assembly 428 passes beyond thelower edge of the profile 504. After passing the profile 504, the c-ringmay expand back outward and prevent the dog seal mandrel 408 from movingback in an axially upward direction.

In addition, the downward motion of the piston assembly 490 mayreposition the lower dog seal mandrel 414 such that the ports 429through the lower dog seal mandrel 414 and the ports 434 through thespacer 430A are aligned with the ports 204 through the outer body 206 ofthe cementing tool 102. This allows communication 506 of fluid from thecentral flowbore of the cementing tool 102 through the ports 204 in theouter diameter of the body 206 and into the annulus surrounding thecementing tool 102. As such, the cementing tool 102 may in this secondconfiguration provide top-down cementing.

In addition, the downward motion of the piston assembly 490 may pull theD-seal 438 at an upper end of the release sleeve 412 into an inner sealbore 508 of the upper bushing 400, thereby creating a seal at theinterface of the D-seal 438 and the upper bushing 400. In addition, thekeys 440 that previously prevented motion of the release sleeve 412relative to the dog seal mandrel 408 are uncovered in a radially outwarddirection. This uncovering of the keys 440 may later allow shear screwsat the same location to shear.

As shown in FIGS. 5A-5B, the ball 200 remains seated within the rotatingball assembly 420 during the entire top-down cementing operation.Seating a ball 200 at this location within the cementing tool 102 andpressuring up to provide the top-down cementing operation may beparticularly useful. First, this configuration does not require a cementwiper plug to land/bump at a lower end of the work string. Instead, theball 200 is landed at a relatively higher position (within the cementingtool 102) for the entire second stage of top-down cementing. Inaddition, there is no need to wait for the bottom-up cement to set priorto conducting the top-down cement job (e.g., due to the possibility of awet shoe). This can save a considerable amount of rig time. In addition,the disclosed cementing tool 102 closes off the drill pipe below theball seat 202 so that all of the top-down cement job is routed to theannulus as opposed to being routed through the liner hanger setting toolbelow.

Once the top-down cementing job is completed, the cementing tool 102 maythen be shifted to the third configuration for reestablishing fluid flowthrough its central flowbore and releasing the ball 200 to set the linerhanger. FIGS. 6A-10B show this progression. The process begins at FIGS.6A and 6B with dropping and pumping a relatively larger second ball (ordart/plug) 300 into the cementing tool 102. In some embodiments, theball or dart may have an outer diameter of between approximately 1.5 and5.5 inches, more particularly between approximately 2.5 and 4.5 inches,or more particularly approximately 3.5 inches. Regardless of the exactsize of the ball, dart, or plug 300, the outer diameter of the ball,dart, or plug 300 is greater than the diameter of the previously droppedball (e.g., 200). This enables the previously dropped ball 200 to landin the lower seat prior to dropping the ball, dart, or plug 300 andshifting the cementing tool 102 from the second configuration to thethird configuration. The ball, dart, or plug 300 may catch in the seat302 formed along the inner diameter of the release sleeve 412, as shownin FIG. 6A.

The release sleeve 412 and components of the cementing tool 102 abovethe release sleeve 412 are sized with an inner diameter that is largeenough to pass a ball, dart, or plug. As such, while a ball (e.g., 200)is used to transition the cementing tool 102 from the first to thesecond configuration, another ball, dart, or plug 300 may be used totransition the cementing tool 102 from the second to the third position.This is different from other top-down cementing tools that generallyrequire the use of dropped balls only to reconfigure the cementing tool.When a dart or plug is used for component 300, the dart or plug mayinclude wiper features extending radially outward therefrom and designedto clear cement from the inner diameter of the drill pipe located abovethe cementing tool 102.

Upon dropping and seating the ball, dart, or plug 300 in the seat 302,this initially creates a piston 610 with its outer seal at an o-ring 600between an outer diameter of the release sleeve 412 and an innerdiameter of the dog seal mandrel 408. This initial piston 610 generallyincludes the release sleeve 412.

Pressure is increased behind the ball or plug 300. This increasedpressure may shear one or more shear screws located between an outerdiameter of the release sleeve 412 and an inner diameter of the dog sealmandrel 408, allowing the release sleeve 412 to then move downwardrelative to the dog seal mandrel 408. Although the shear screw(s) arenot visible in the view of FIGS. 6A-6B, these shear screw(s) 650 areshown in FIG. 11.

FIGS. 7A-7B illustrate the resulting downward movement of the releasesleeve 412 relative to the dog seal mandrel 408 as the piston assembly610 begins to stroke downward. This movement may cause a groove 700formed along an outer diameter of the release sleeve 412 to move underthe load lugs 426, thereby unloading the load lugs 426 from theirposition against the inner diameter (and against the shoulder 502) ofthe locating sleeve 406. This allows the load lugs 426 to move past theshoulder 502 of the locating sleeve 406, allowing the dog seal mandrel408 to move axially downward with the release sleeve 412 relative to thebody 206. At this point, the dog seal mandrel 408 may form part of thepiston assembly 610 as well. As the release sleeve 412 and the rest ofthe piston assembly 610 move downward, the D-seal 438 at the top of therelease sleeve 412 may be uncovered (i.e., disengaged from the seal boreof the upper bushing 400) and this allows pressure to reach theuppermost bonded seal 430 surrounding the lower dog seal mandrel 414.This uppermost bonded seal 430 may then define a hydraulic piston areafor a new piston assembly 710. Below the uppermost bonded seal 430, thecomponents of the cementing tool 102 are not under applied pressure.

As the new piston assembly 710 (including the lower dog seal mandrel 414and associated bonded seals 430) moves downward, the flow path to theannulus surrounding the cementing tool 102 may be shut off, as shown inFIGS. 8A and 8B. Specifically, the piston assembly 710 may move downwardrelative to the body 206 until the bonded seals 430 separate the ports429 through the lower dog seal mandrel 414 from the ports 204 throughthe body 206.

In addition, as the piston assembly 710 moves downward the shift sleeve422 may contact a shoulder 800 formed on an inner diameter of the body206. This may cause one or more shear screws located between the shiftsleeve 422 and the ball mandrel 421 to shear. Although these shearscrew(s) are not visible in the view of FIGS. 8A-8B, these shearscrew(s) 850 are shown in FIG. 12. FIG. 12 is a section view of thecementing tool 102 taken at line B-B of FIG. 4B before the shearscrew(s) 850 have been sheared (i.e., when the cementing tool 102 isstill in the first configuration). Upon shearing the screw(s) 850between the shift sleeve 422 and the ball mandrel 421, the rotating ballassembly 420 is able to be actuated to rotate the ball 446 as discussedbelow.

As the piston assembly 710 continues to move downward, the ball mandrel421 may move axially downward with respect to the shift sleeve 422, asshown in FIGS. 9A-9B. This movement may cause the set of release dogs450 in the outer diameter of the ball mandrel 421 to be uncovered andexpand radially outward into the grooves 449 within the shift sleeve422. The release dogs 450 are thus disengaged from a correspondinggroove in the outer diameter of the lower seat 444 of the rotating ballassembly 420. The lower seat 444 may then be pushed downward by therotating ball 446, whose mechanism is being pushed downward by thecompression spring 448. Cam mechanisms of the rotating ball assembly 420rotate the ball 446 from the orientation with the restricted flowpath toan orientation with an enlarged flowpath 900 in the axial direction.This rotation of the ball 446 allows the previously seated ball 200 tobe released from the seat and to travel downhole toward the liner hangersetting tool, where the ball 200 can be used to set the liner. Using therotating ball assembly 420 to release the ball 200, as opposed to anexpandable cone, provides a fully unrestricted bore through thecementing tool 102 for any process that comes after the cementingoperation.

A lower end of the piston assembly 710 (e.g., at the radially extendedportion of the ball mandrel 421) may be caught on a shoulder 902 of theshift sleeve 422. Continued increasing pressure on the piston assembly710 may move the release sleeve 412 further downward, pushing the loadlugs 426 radially outward via a slanted edge of the groove 700 until theload lugs 426 move completely out of the groove 700 in the releasesleeve 412. With the load lugs 426 out of the groove 700, the releasesleeve 412 is able to shift further axially downward, as shown in FIGS.10A-10B. As the release sleeve 412 moves axially downward inside of thedog seal mandrel 408, this may open a new flow path 970 that directsfluid flow around the outer diameter of the release sleeve 412 and thenthrough the slots 424 and 436 in the dog seal mandrel 408 and therelease sleeve 412, respectively. This flow path 970 bypasses the ball,dart, or plug 300, which remains landed in the seat 302. This mayrestore a through flowpath within the cementing tool 102, therebyplacing the cementing tool 102 in the third configuration.

Although the present disclosure and its advantages have been describedin detail, it should be understood that various changes, substitutionsand alterations can be made herein without departing from the spirit andscope of the disclosure as defined by the following claims.

What is claimed is:
 1. A cementing tool, comprising: a body; one or moreports extending through the body; a first seat internal to the body andconfigured to receive a ball landed thereon; a second seat internal tothe body and configured to receive a ball, dart, or plug landed thereon;and a shifting sleeve assembly internal to the body and configured toselectively transition the cementing tool from a first operating mode toa second operating mode and from the second operating mode to a thirdoperating mode, wherein: in the first operating mode, a central flowboreof the cementing tool is open; in the second operating mode, a ball islanded on the first seat, at least a portion of the central flowbore isclosed, and the one or more ports are open; and in the third operatingmode, the ball is released from the first seat, a ball, dart, or plug islanded on the second seat, and the shifting sleeve forms an internalflow path that circumvents the second seat.
 2. The cementing tool ofclaim 1, further comprising an actuator coupled to the first seat,wherein the first seat is configured to release the ball therefrom uponactuation of the first seat by the actuator.
 3. The cementing tool ofclaim 1, wherein the first seat comprises a rotatable ball having twodifferent sized flow paths formed therethrough, wherein the rotatableball is rotatable between a first position in which a first flow path isaligned with the central flowbore and a second position in which asecond flow path is aligned with the central flowbore.
 4. The cementingtool of claim 1, wherein the first seat is configured to receive a ballhaving a first outer diameter thereon and wherein the second seat isconfigured to receive a ball, dart, or plug having a second outerdiameter thereon, the second outer diameter being greater than the firstouter diameter.
 5. The cementing tool of claim 1, wherein the secondseat is located axially above the first seat.
 6. The cementing tool ofclaim 5, wherein the one or more ports are located at an axial positionbetween the first seat and the second seat.
 7. A liner installation workstring, comprising: a liner hanger setting tool; and a cementing toolcoupled to the liner hanger setting tool and having a central flowborein fluid communication with a flowbore of the liner hanger setting tool,the cementing tool comprising: a body; one or more ports extendingthrough the body; a first seat internal to the body and configured toreceive a ball landed thereon; a second seat internal to the body andconfigured to receive a ball, dart, or plug landed thereon; and ashifting sleeve assembly internal to the body and configured toselectively transition the cementing tool from a first operating mode toa second operating mode and from the second operating mode to a thirdoperating mode, wherein: in the first operating mode, the centralflowbore of the cementing tool is open; in the second operating mode, aball is landed on the first seat, at least a portion of the centralflowbore is closed, and the one or more ports are open; and in the thirdoperating mode, the ball is released from the first seat, a ball, dart,or plug is landed on the second seat, and the shifting sleeve forms aninternal flow path that circumvents the second seat.
 8. The linerinstallation work string of claim 7, wherein the liner hanger settingtool comprises a third seat configured to receive a ball landed thereonto set the liner hanger.
 9. The liner installation work string of claim8, wherein: the first seat is configured to receive a ball having afirst outer diameter thereon; the second seat is configured to receive aball, dart, or plug having a second outer diameter thereon, the secondouter diameter being greater than the first outer diameter; and thethird seat is configured to receive a ball having a diameter equal to orless than the first outer diameter thereon.
 10. The liner installationwork string of claim 7, further comprising an actuator coupled to thefirst seat, wherein the first seat is configured to release the balltherefrom upon actuation of the first seat by the actuator.
 11. Theliner installation work string of claim 7, wherein the first seatcomprises a rotatable ball having two different sized flow paths formedtherethrough, wherein the rotatable ball is rotatable between a firstposition in which a first flow path is aligned with the central flowboreand a second position in which a second flow path is aligned with thecentral flowbore.
 12. The liner installation work string of claim 7,wherein the second seat is located axially above the first seat.
 13. Theliner installation work string of claim 12, wherein the one or moreports are located at an axial position between the first seat and thesecond seat.
 14. A liner installation method, comprising: providing acementing tool coupled to a liner hanger setting tool, wherein thecementing tool comprises: a body; one or more ports extending throughthe body; a first seat internal to the body and configured to receive aball landed thereon; a second seat internal to the body and configuredto receive a ball, dart, or plug landed thereon; and a shifting sleeveassembly internal to the body and configured to selectively transitionthe cementing tool from a first operating mode to a second operatingmode and from the second operating mode to a third operating mode,wherein: in the first operating mode, a central flowbore of thecementing tool is open; in the second operating mode, a ball is landedon the first seat, at least a portion of the central flowbore is closed,and the one or more ports are open; and in the third operating mode, theball is released from the first seat, a ball, dart, or plug is landed onthe second seat, and the shifting sleeve forms an internal flow paththat circumvents the second seat; cementing a liner coupled to the linerhanger setting tool in a wellbore via the cementing tool; and setting aliner hanger holding the liner via the liner hanger setting tool. 15.The liner installation method of claim 14, further comprising: while thecementing tool is in the first operating mode, circulating cementthrough the central flowbore, the liner hanger setting tool, and theliner to cement the liner in the wellbore from bottom-up; shifting thecementing tool from the first operating mode to the second operatingmode; while the cementing tool is in the second operating mode, routingcement through the one or more ports into an annulus surrounding thecementing tool to cement the liner in the wellbore from top-down;shifting the cementing tool from the second operating mode to the thirdoperating mode to reestablish flow into a flowbore of the liner hangersetting tool; and while the cementing tool is in the third operatingmode, setting the liner hanger.
 16. The liner installation method ofclaim 15, wherein: shifting the cementing tool from the first operatingmode to the second operating mode comprises landing the ball on thefirst seat; shifting the cementing tool from the second operating modeto the third operating mode comprises landing the ball, dart, or plug onthe second seat and releasing the ball from the first seat; and settingthe liner hanger comprises landing the ball released from the first seatonto a third seat in the liner hanger setting tool.
 17. The linerinstallation method of claim 15, further comprising cementing the linerin the wellbore from top-down before the cement circulated through theliner to cement the liner from bottom-up is dry.
 18. The linerinstallation method of claim 14, further comprising: while the cementingtool is in the first operating mode, circulating cement through thecentral flowbore, the liner hanger setting tool, and the liner to cementthe liner in the wellbore from bottom-up; and while the cementing toolis in the first operating mode, and without shifting the cementing toolinto the second or third operating modes, setting the liner hanger. 19.The liner installation method of claim 18, wherein setting the linerhanger comprises landing a ball on a third seat in the liner hangersetting tool.